// This source file is part of the polarphp.org open source project
//
// Copyright (c) 2017 - 2018 polarphp software foundation
// Copyright (c) 2017 - 2018 zzu_softboy <zzu_softboy@163.com>
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://polarphp.org/LICENSE.txt for license information
// See https://polarphp.org/CONTRIBUTORS.txt for the list of polarphp project authors
//
// Created by polarboy on 2018/06/06.

#include "polarphp/basic/adt/DenseMap.h"
#include "gtest/gtest.h"
#include <map>
#include <set>

namespace {

using polar::basic::DenseMap;
using polar::basic::SmallDenseMap;
using polar::basic::StringRef;

uint32_t getTestKey(int i, uint32_t *) { return i; }
uint32_t getTestValue(int i, uint32_t *) { return 42 + i; }

uint32_t *getTestKey(int i, uint32_t **) {
   static uint32_t dummy_arr1[8192];
   assert(i < 8192 && "Only support 8192 dummy keys.");
   return &dummy_arr1[i];
}
uint32_t *getTestValue(int i, uint32_t **) {
   static uint32_t dummy_arr1[8192];
   assert(i < 8192 && "Only support 8192 dummy keys.");
   return &dummy_arr1[i];
}

/// \brief A test class that tries to check that construction and destruction
/// occur correctly.
class CtorTester {
   static std::set<CtorTester *> Constructed;
   int Value;

public:
   explicit CtorTester(int Value = 0) : Value(Value) {
      EXPECT_TRUE(Constructed.insert(this).second);
   }
   CtorTester(uint32_t Value) : Value(Value) {
      EXPECT_TRUE(Constructed.insert(this).second);
   }
   CtorTester(const CtorTester &Arg) : Value(Arg.Value) {
      EXPECT_TRUE(Constructed.insert(this).second);
   }
   CtorTester &operator=(const CtorTester &) = default;
   ~CtorTester() {
      EXPECT_EQ(1u, Constructed.erase(this));
   }
   operator uint32_t() const { return Value; }

   int getValue() const { return Value; }
   bool operator==(const CtorTester &RHS) const { return Value == RHS.Value; }
};

std::set<CtorTester *> CtorTester::Constructed;

struct CtorTesterMapInfo {
   static inline CtorTester getEmptyKey() { return CtorTester(-1); }
   static inline CtorTester getTombstoneKey() { return CtorTester(-2); }
   static unsigned getHashValue(const CtorTester &Val) {
      return Val.getValue() * 37u;
   }
   static bool isEqual(const CtorTester &LHS, const CtorTester &RHS) {
      return LHS == RHS;
   }
};

CtorTester getTestKey(int i, CtorTester *) { return CtorTester(i); }
CtorTester getTestValue(int i, CtorTester *) { return CtorTester(42 + i); }

// Test fixture, with helper functions implemented by forwarding to global
// function overloads selected by component types of the type parameter. This
// allows all of the map implementations to be tested with shared
// implementations of helper routines.
template <typename T>
class DenseMapTest : public ::testing::Test
{
protected:
   T Map;

   static typename T::key_type *const dummy_key_ptr;
   static typename T::mapped_type *const dummy_value_ptr;

   typename T::key_type getKey(int i = 0) {
      return getTestKey(i, dummy_key_ptr);
   }
   typename T::mapped_type getValue(int i = 0) {
      return getTestValue(i, dummy_value_ptr);
   }
};

template <typename T>
typename T::key_type *const DenseMapTest<T>::dummy_key_ptr = nullptr;
template <typename T>
typename T::mapped_type *const DenseMapTest<T>::dummy_value_ptr = nullptr;

// Register these types for testing.
typedef ::testing::Types<DenseMap<uint32_t, uint32_t>,
DenseMap<uint32_t *, uint32_t *>,
DenseMap<CtorTester, CtorTester, CtorTesterMapInfo>,
SmallDenseMap<uint32_t, uint32_t>,
SmallDenseMap<uint32_t *, uint32_t *>,
SmallDenseMap<CtorTester, CtorTester, 4,
CtorTesterMapInfo>
> DenseMapTestTypes;
TYPED_TEST_CASE(DenseMapTest, DenseMapTestTypes);

// Empty map tests
TYPED_TEST(DenseMapTest, testEmptyIntMap)
{
   // Size tests
   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());

   // Iterator tests
   EXPECT_TRUE(this->Map.begin() == this->Map.end());

   // Lookup tests
   EXPECT_FALSE(this->Map.count(this->getKey()));
   EXPECT_TRUE(this->Map.find(this->getKey()) == this->Map.end());
#if !defined(_MSC_VER) || defined(__clang__)
   EXPECT_EQ(typename TypeParam::mapped_type(),
             this->Map.lookup(this->getKey()));
#else
   // MSVC, at least old versions, cannot parse the typename to disambiguate
   // TypeParam::mapped_type as a type. However, because MSVC doesn't implement
   // two-phase name lookup, it also doesn't require the typename. Deal with
   // this mutual incompatibility through specialized code.
   EXPECT_EQ(TypeParam::mapped_type(),
             this->Map.lookup(this->getKey()));
#endif
}

// Constant map tests
TYPED_TEST(DenseMapTest, testConstEmptyMap)
{
   const TypeParam &ConstMap = this->Map;
   EXPECT_EQ(0u, ConstMap.getSize());
   EXPECT_TRUE(ConstMap.empty());
   EXPECT_TRUE(ConstMap.begin() == ConstMap.end());
}

// A map with a single entry
TYPED_TEST(DenseMapTest, testSingleEntryMap)
{
   this->Map[this->getKey()] = this->getValue();

   // Size tests
   EXPECT_EQ(1u, this->Map.getSize());
   EXPECT_FALSE(this->Map.begin() == this->Map.end());
   EXPECT_FALSE(this->Map.empty());

   // Iterator tests
   typename TypeParam::iterator it = this->Map.begin();
   EXPECT_EQ(this->getKey(), it->first);
   EXPECT_EQ(this->getValue(), it->second);
   ++it;
   EXPECT_TRUE(it == this->Map.end());

   // Lookup tests
   EXPECT_TRUE(this->Map.count(this->getKey()));
   EXPECT_TRUE(this->Map.find(this->getKey()) == this->Map.begin());
   EXPECT_EQ(this->getValue(), this->Map.lookup(this->getKey()));
   EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
}

// Test clear() method
TYPED_TEST(DenseMapTest, testClear)
{
   this->Map[this->getKey()] = this->getValue();
   this->Map.clear();

   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());
   EXPECT_TRUE(this->Map.begin() == this->Map.end());
}

// Test erase(iterator) method
TYPED_TEST(DenseMapTest, testErase)
{
   this->Map[this->getKey()] = this->getValue();
   this->Map.erase(this->Map.begin());

   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());
   EXPECT_TRUE(this->Map.begin() == this->Map.end());
}

// Test erase(value) method
TYPED_TEST(DenseMapTest, testEraseTest2)
{
   this->Map[this->getKey()] = this->getValue();
   this->Map.erase(this->getKey());

   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());
   EXPECT_TRUE(this->Map.begin() == this->Map.end());
}

// Test insert() method
TYPED_TEST(DenseMapTest, testInsert)
{
   this->Map.insert(std::make_pair(this->getKey(), this->getValue()));
   EXPECT_EQ(1u, this->Map.getSize());
   EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
}

// Test copy constructor method
TYPED_TEST(DenseMapTest, testCopyConstructor)
{
   this->Map[this->getKey()] = this->getValue();
   TypeParam copyMap(this->Map);

   EXPECT_EQ(1u, copyMap.getSize());
   EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);
}

// Test copy constructor method where SmallDenseMap isn't small.
TYPED_TEST(DenseMapTest, testCopyConstructorNotSmall)
{
   for (int Key = 0; Key < 5; ++Key)
      this->Map[this->getKey(Key)] = this->getValue(Key);
   TypeParam copyMap(this->Map);

   EXPECT_EQ(5u, copyMap.getSize());
   for (int Key = 0; Key < 5; ++Key)
      EXPECT_EQ(this->getValue(Key), copyMap[this->getKey(Key)]);
}

// Test copying from a default-constructed map.
TYPED_TEST(DenseMapTest, testCopyConstructorFromDefault)
{
   TypeParam copyMap(this->Map);

   EXPECT_TRUE(copyMap.empty());
}

// Test copying from an empty map where SmallDenseMap isn't small.
TYPED_TEST(DenseMapTest, testCopyConstructorFromEmpty)
{
   for (int Key = 0; Key < 5; ++Key)
      this->Map[this->getKey(Key)] = this->getValue(Key);
   this->Map.clear();
   TypeParam copyMap(this->Map);

   EXPECT_TRUE(copyMap.empty());
}

// Test assignment operator method
TYPED_TEST(DenseMapTest, testAssignment)
{
   this->Map[this->getKey()] = this->getValue();
   TypeParam copyMap = this->Map;

   EXPECT_EQ(1u, copyMap.getSize());
   EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);

   // test self-assignment.
   copyMap = static_cast<TypeParam &>(copyMap);
   EXPECT_EQ(1u, copyMap.getSize());
   EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);
}

TYPED_TEST(DenseMapTest, testAssignmentTestNotSmall)
{
   for (int Key = 0; Key < 5; ++Key)
      this->Map[this->getKey(Key)] = this->getValue(Key);
   TypeParam copyMap = this->Map;

   EXPECT_EQ(5u, copyMap.getSize());
   for (int Key = 0; Key < 5; ++Key)
      EXPECT_EQ(this->getValue(Key), copyMap[this->getKey(Key)]);

   // test self-assignment.
   copyMap = static_cast<TypeParam &>(copyMap);
   EXPECT_EQ(5u, copyMap.getSize());
   for (int Key = 0; Key < 5; ++Key)
      EXPECT_EQ(this->getValue(Key), copyMap[this->getKey(Key)]);
}

// Test swap method
TYPED_TEST(DenseMapTest, testSwap)
{
   this->Map[this->getKey()] = this->getValue();
   TypeParam otherMap;

   this->Map.swap(otherMap);
   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());
   EXPECT_EQ(1u, otherMap.getSize());
   EXPECT_EQ(this->getValue(), otherMap[this->getKey()]);

   this->Map.swap(otherMap);
   EXPECT_EQ(0u, otherMap.getSize());
   EXPECT_TRUE(otherMap.empty());
   EXPECT_EQ(1u, this->Map.getSize());
   EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);

   // Make this more interesting by inserting 100 numbers into the map.
   for (int i = 0; i < 100; ++i)
      this->Map[this->getKey(i)] = this->getValue(i);

   this->Map.swap(otherMap);
   EXPECT_EQ(0u, this->Map.getSize());
   EXPECT_TRUE(this->Map.empty());
   EXPECT_EQ(100u, otherMap.getSize());
   for (int i = 0; i < 100; ++i)
      EXPECT_EQ(this->getValue(i), otherMap[this->getKey(i)]);

   this->Map.swap(otherMap);
   EXPECT_EQ(0u, otherMap.getSize());
   EXPECT_TRUE(otherMap.empty());
   EXPECT_EQ(100u, this->Map.getSize());
   for (int i = 0; i < 100; ++i)
      EXPECT_EQ(this->getValue(i), this->Map[this->getKey(i)]);
}

// A more complex iteration test
TYPED_TEST(DenseMapTest, testIteration)
{
   bool visited[100];
   std::map<typename TypeParam::key_type, unsigned> visitedIndex;

   // Insert 100 numbers into the map
   for (int i = 0; i < 100; ++i) {
      visited[i] = false;
      visitedIndex[this->getKey(i)] = i;

      this->Map[this->getKey(i)] = this->getValue(i);
   }

   // Iterate over all numbers and mark each one found.
   for (typename TypeParam::iterator it = this->Map.begin();
        it != this->Map.end(); ++it)
      visited[visitedIndex[it->first]] = true;

   // Ensure every number was visited.
   for (int i = 0; i < 100; ++i)
      ASSERT_TRUE(visited[i]) << "Entry #" << i << " was never visited";
}

// const_iterator test
TYPED_TEST(DenseMapTest, testConstIterator)
{
   // Check conversion from iterator to const_iterator.
   typename TypeParam::iterator it = this->Map.begin();
   typename TypeParam::const_iterator cit(it);
   EXPECT_TRUE(it == cit);

   // Check copying of const_iterators.
   typename TypeParam::const_iterator cit2(cit);
   EXPECT_TRUE(cit == cit2);
}

namespace {
// Simple class that counts how many moves and copy happens when growing a map
struct CountCopyAndMove
{
   static int Move;
   static int Copy;
   CountCopyAndMove() {}

   CountCopyAndMove(const CountCopyAndMove &) { Copy++; }
   CountCopyAndMove &operator=(const CountCopyAndMove &) {
      Copy++;
      return *this;
   }
   CountCopyAndMove(CountCopyAndMove &&) { Move++; }
   CountCopyAndMove &operator=(const CountCopyAndMove &&) {
      Move++;
      return *this;
   }
};
int CountCopyAndMove::Copy = 0;
int CountCopyAndMove::Move = 0;

} // anonymous namespace

// Test initializer list construction.
TEST(DenseMapCustomTest, testInitializerList)
{
   DenseMap<int, int> M({{0, 0}, {0, 1}, {1, 2}});
   EXPECT_EQ(2u, M.getSize());
   EXPECT_EQ(1u, M.count(0));
   EXPECT_EQ(0, M[0]);
   EXPECT_EQ(1u, M.count(1));
   EXPECT_EQ(2, M[1]);
}

// Test initializer list construction.
TEST(DenseMapCustomTest, testEqualityComparison)
{
   DenseMap<int, int> M1({{0, 0}, {1, 2}});
   DenseMap<int, int> M2({{0, 0}, {1, 2}});
   DenseMap<int, int> M3({{0, 0}, {1, 3}});

   EXPECT_EQ(M1, M2);
   EXPECT_NE(M1, M3);
}

// Test for the default minimum size of a DenseMap
TEST(DenseMapCustomTest, testDefaultMinReservedSize)
{
   // IF THIS VALUE CHANGE, please update InitialSizeTest, InitFromIterator, and
   // ReserveTest as well!
   const int ExpectedInitialBucketCount = 64;
   // Formula from DenseMap::getMinBucketToReserveForEntries()
   const int ExpectedMaxInitialEntries = ExpectedInitialBucketCount * 3 / 4 - 1;

   DenseMap<int, CountCopyAndMove> Map;
   // Will allocate 64 buckets
   Map.reserve(1);
   unsigned MemorySize = Map.getMemorySize();
   CountCopyAndMove::Copy = 0;
   CountCopyAndMove::Move = 0;
   for (int i = 0; i < ExpectedMaxInitialEntries; ++i)
      Map.insert(std::pair<int, CountCopyAndMove>(std::piecewise_construct,
                                                  std::forward_as_tuple(i),
                                                  std::forward_as_tuple()));
   // Check that we didn't grow
   EXPECT_EQ(MemorySize, Map.getMemorySize());
   // Check that move was called the expected number of times
   EXPECT_EQ(ExpectedMaxInitialEntries, CountCopyAndMove::Move);
   // Check that no copy occured
   EXPECT_EQ(0, CountCopyAndMove::Copy);

   // Adding one extra element should grow the map
   Map.insert(std::pair<int, CountCopyAndMove>(
                 std::piecewise_construct,
                 std::forward_as_tuple(ExpectedMaxInitialEntries),
                 std::forward_as_tuple()));
   // Check that we grew
   EXPECT_NE(MemorySize, Map.getMemorySize());
   // Check that move was called the expected number of times
   //  This relies on move-construction elision, and cannot be reliably tested.
   //   EXPECT_EQ(ExpectedMaxInitialEntries + 2, CountCopyAndMove::Move);
   // Check that no copy occured
   EXPECT_EQ(0, CountCopyAndMove::Copy);
}

// Make sure creating the map with an initial size of N actually gives us enough
// buckets to insert N items without increasing allocation size.
TEST(DenseMapCustomTest, testInitialSize)
{
   // Test a few different sizes, 48 is *not* a random choice: we need a value
   // that is 2/3 of a power of two to stress the grow() condition, and the power
   // of two has to be at least 64 because of minimum size allocation in the
   // DenseMap (see DefaultMinReservedSize). 66 is a value just above the
   // 64 default init.
   for (auto Size : {1, 2, 48, 66}) {
      DenseMap<int, CountCopyAndMove> Map(Size);
      unsigned MemorySize = Map.getMemorySize();
      CountCopyAndMove::Copy = 0;
      CountCopyAndMove::Move = 0;
      for (int i = 0; i < Size; ++i)
         Map.insert(std::pair<int, CountCopyAndMove>(std::piecewise_construct,
                                                     std::forward_as_tuple(i),
                                                     std::forward_as_tuple()));
      // Check that we didn't grow
      EXPECT_EQ(MemorySize, Map.getMemorySize());
      // Check that move was called the expected number of times
      EXPECT_EQ(Size, CountCopyAndMove::Move);
      // Check that no copy occured
      EXPECT_EQ(0, CountCopyAndMove::Copy);
   }
}

// Make sure creating the map with a iterator range does not trigger grow()
TEST(DenseMapCustomTest, testInitFromIterator)
{
   std::vector<std::pair<int, CountCopyAndMove>> Values;
   // The size is a random value greater than 64 (hardcoded DenseMap min init)
   const int Count = 65;
   for (int i = 0; i < Count; i++)
      Values.emplace_back(i, CountCopyAndMove());

   CountCopyAndMove::Move = 0;
   CountCopyAndMove::Copy = 0;
   DenseMap<int, CountCopyAndMove> Map(Values.begin(), Values.end());
   // Check that no move occured
   EXPECT_EQ(0, CountCopyAndMove::Move);
   // Check that copy was called the expected number of times
   EXPECT_EQ(Count, CountCopyAndMove::Copy);
}

// Make sure reserve actually gives us enough buckets to insert N items
// without increasing allocation size.
TEST(DenseMapCustomTest, testReserve)
{
   // Test a few different size, 48 is *not* a random choice: we need a value
   // that is 2/3 of a power of two to stress the grow() condition, and the power
   // of two has to be at least 64 because of minimum size allocation in the
   // DenseMap (see DefaultMinReservedSize). 66 is a value just above the
   // 64 default init.
   for (auto Size : {1, 2, 48, 66}) {
      DenseMap<int, CountCopyAndMove> Map;
      Map.reserve(Size);
      unsigned MemorySize = Map.getMemorySize();
      CountCopyAndMove::Copy = 0;
      CountCopyAndMove::Move = 0;
      for (int i = 0; i < Size; ++i)
         Map.insert(std::pair<int, CountCopyAndMove>(std::piecewise_construct,
                                                     std::forward_as_tuple(i),
                                                     std::forward_as_tuple()));
      // Check that we didn't grow
      EXPECT_EQ(MemorySize, Map.getMemorySize());
      // Check that move was called the expected number of times
      EXPECT_EQ(Size, CountCopyAndMove::Move);
      // Check that no copy occured
      EXPECT_EQ(0, CountCopyAndMove::Copy);
   }
}

// Make sure DenseMap works with StringRef keys.
TEST(DenseMapCustomTest, testStringRef)
{
   DenseMap<StringRef, int> M;

   M["a"] = 1;
   M["b"] = 2;
   M["c"] = 3;

   EXPECT_EQ(3u, M.getSize());
   EXPECT_EQ(1, M.lookup("a"));
   EXPECT_EQ(2, M.lookup("b"));
   EXPECT_EQ(3, M.lookup("c"));

   EXPECT_EQ(0, M.lookup("q"));

   // Test the empty string, spelled various ways.
   EXPECT_EQ(0, M.lookup(""));
   EXPECT_EQ(0, M.lookup(StringRef()));
   EXPECT_EQ(0, M.lookup(StringRef("a", 0)));
   M[""] = 42;
   EXPECT_EQ(42, M.lookup(""));
   EXPECT_EQ(42, M.lookup(StringRef()));
   EXPECT_EQ(42, M.lookup(StringRef("a", 0)));
}

// Key traits that allows lookup with either an unsigned or char* key;
// In the latter case, "a" == 0, "b" == 1 and so on.
struct TestDenseMapInfo
{
   static inline unsigned getEmptyKey() { return ~0; }
   static inline unsigned getTombstoneKey() { return ~0U - 1; }
   static unsigned getHashValue(const unsigned& Val) { return Val * 37U; }
   static unsigned getHashValue(const char* Val) {
      return (unsigned)(Val[0] - 'a') * 37U;
   }
   static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
      return LHS == RHS;
   }
   static bool isEqual(const char* LHS, const unsigned& RHS) {
      return (unsigned)(LHS[0] - 'a') == RHS;
   }
};

// findAs() tests
TEST(DenseMapCustomTest, testFindAs)
{
   DenseMap<unsigned, unsigned, TestDenseMapInfo> map;
   map[0] = 1;
   map[1] = 2;
   map[2] = 3;

   // Size tests
   EXPECT_EQ(3u, map.getSize());

   // Normal lookup tests
   EXPECT_EQ(1u, map.count(1));
   EXPECT_EQ(1u, map.find(0)->second);
   EXPECT_EQ(2u, map.find(1)->second);
   EXPECT_EQ(3u, map.find(2)->second);
   EXPECT_TRUE(map.find(3) == map.end());

   // findAs() tests
   EXPECT_EQ(1u, map.findAs("a")->second);
   EXPECT_EQ(2u, map.findAs("b")->second);
   EXPECT_EQ(3u, map.findAs("c")->second);
   EXPECT_TRUE(map.findAs("d") == map.end());
}

struct ContiguousDenseMapInfo
{
   static inline unsigned getEmptyKey() { return ~0; }
   static inline unsigned getTombstoneKey() { return ~0U - 1; }
   static unsigned getHashValue(const unsigned& Val) { return Val; }
   static bool isEqual(const unsigned& LHS, const unsigned& RHS) {
      return LHS == RHS;
   }
};

// Test that filling a small dense map with exactly the number of elements in
// the map grows to have enough space for an empty bucket.
TEST(DenseMapCustomTest, testSmallDenseMapGrow)
{
   SmallDenseMap<unsigned, unsigned, 32, ContiguousDenseMapInfo> map;
   // Add some number of elements, then delete a few to leave us some tombstones.
   // If we just filled the map with 32 elements we'd grow because of not enough
   // tombstones which masks the issue here.
   for (unsigned i = 0; i < 20; ++i)
      map[i] = i + 1;
   for (unsigned i = 0; i < 10; ++i)
      map.erase(i);
   for (unsigned i = 20; i < 32; ++i)
      map[i] = i + 1;

   // Size tests
   EXPECT_EQ(22u, map.getSize());

   // Try to find an element which doesn't exist.  There was a bug in
   // SmallDenseMap which led to a map with num elements == small capacity not
   // having an empty bucket any more.  Finding an element not in the map would
   // therefore never terminate.
   EXPECT_TRUE(map.find(32) == map.end());
}

TEST(DenseMapCustomTest, testTryEmplace)
{
   DenseMap<int, std::unique_ptr<int>> Map;
   std::unique_ptr<int> P(new int(2));
   auto Try1 = Map.tryEmplace(0, new int(1));
   EXPECT_TRUE(Try1.second);
   auto Try2 = Map.tryEmplace(0, std::move(P));
   EXPECT_FALSE(Try2.second);
   EXPECT_EQ(Try1.first, Try2.first);
   EXPECT_NE(nullptr, P);
}

TEST(DenseMapCustomTest, testConst)
{
   // Test that const pointers work okay for count and find, even when the
   // underlying map is a non-const pointer.
   DenseMap<int *, int> Map;
   int A;
   int *B = &A;
   const int *C = &A;
   Map.insert({B, 0});
   EXPECT_EQ(Map.count(B), 1u);
   EXPECT_EQ(Map.count(C), 1u);
   EXPECT_NE(Map.find(B), Map.end());
   EXPECT_NE(Map.find(C), Map.end());
}

} // anonymous namespace
